Worldwide, TB causes more human deaths than any other infectious disease and most of these deaths occur in developing countries where access to improved diagnostic tools is lacking. The key to controlling the TB epidemic is the early identification and treatment of patients with latent disease before conversion to active disease. This SBIR project addresses the important need for a point of care assay for identifying individuals infected with latent and active tuberculosis (TB). Serological based assays are readily adaptable to point-of-care resources, however, for TB, no diagnostic antigen determinants have been defined. Of the dozens of TB- associated antigens investigated, none are sufficiently immunodominant to be reliable for a classical immunoassay based diagnostic. In this project, we address this problem with a protein multiplex microarray that is capable of detecting in a single experiment, a large number of diverse antibodies that are generated in the humoral response to TB antigens. The diagnostic power of the test will increase directly with the number of antigens that can be analyzed. The ability to look at hundreds of defined antigens, with increased sensitivity and specificity should allow a more robust and accurate analysis which can detect infected individuals and differentiate between latent and active stages of infection. The proposed platform is orders of magnitude more sensitive than ELISA formats. This increased sensitivity combined with the ease of detecting IgA class antibodies (IgA response is often less effected than the IgG response in immune-compromised individuals) will permit the use of the test for patients with other co-morbidities e.g. HIV infection. In Phase I, we will test the feasibility of the multiplex microarray platform with a limited number of clinically defined samples. The successful completion of Phase II will produce an improved, rapid, point of care detection and screening assay for TB infection. [unreadable] [unreadable] Identification of individuals with active tuberculosis (TB) is critical to public health care efforts to prevent the spread of TB. However, accurately identifying and treating individuals who have latent TB, is vital to the over-all control of this disease. Worldwide tuberculosis (TB) causes more human deaths than any other infectious disease. Improved TB diagnostic services are less effective in immune compromised individuals and such services are extremely limited in countries with the highest TB burden and morbidity. An affordable, accurate, accessible immunoassay that enables early identification of latent or active TB is crucial for infection control program success. The proposed multiplex microarray methodology is a practical, efficient system to check for specific, significant TB antibodies. This point-of-care multiplex microarray assay for TB can identify at the point-of-care, latent as well as, active TB infection and therefore drug therapy can begin sooner. [unreadable] [unreadable] [unreadable]